The Spot Price Discovery of Put-call Ratio of KOSPI200 Nighttime Options

Trading of KOSPI200 options on Eurex launched in 2010 starts at 17:00 after market and closes at 05:00 in the next morning. This paper attempts to examine the role of put-call ratio of KOSPI200 nighttime options in price discovery process of spot market. The main findings of this paper are summarized as followings; The information content of put-call ratio of nighttime options is significantly incorporated in opening price of spot market next trading day but not delayed to the daytime spot market. Specifically, all put-call ratios measured in terms of total volume, total value, and cleared volume of nighttime options has strongly positive correlation with returns of KOSPI200 next trading day but put-call ratio of daytime option market has no predictive power of next daily return during sample period. This implies that the nighttime options market shows more leading role than daytime options in opening price discovery. This relationship between put-call ration and spot market return remains statistically significant during the period of the multiplier for KOSPI200 options increased. However, the change in put-call ratio of nighttime options is significantly explained by precedent put-call ratio of daytime market. This Overall empirical evidence indicates that traders of KOSPI200 options have tendency to implement strategy of linkage between price movement of daytime and nighttime market.